A carrier aggregation (CA) technology is introduced in a Long Term Evolution Advanced (LTE-A) system, and two or more component carriers (CC) may be aggregated to support a larger bandwidth. Before the release R12 of LTE-A, the CA technology supports only carrier aggregation between carriers of a same duplex mode, but in the release R12, aggregation between carriers of different duplex modes are allowed. CA defined herein is based on an assumption of ideal backhaul, that is, a very short delay exists in backhaul between different network devices that control CCs or between different units of a same network device, and information can be exchanged quickly. For example, for CA between cells that are of different carriers and that belong to a same evolved Node B (eNodeB), because these cells belong to the same eNodeB, backhaul between the cells is ideal, and information can be exchanged quickly.
In the LTE-A R12 standard, a dual connectivity (Dual Connectivity, DC for short below) technology is introduced, user equipment (UE) may be simultaneously connected to two cells, so that the cells provide a service to the user equipment, where the two cells belong to different eNodeBs, and the eNodeBs are connected by means of non-ideal backhaul. A schematic diagram of dual connectivity is shown in FIG. 1, where carriers CC1 and CC2 are used in a macro cell and a small cell respectively, a duplex mode of the CC1 is frequency division duplex (FDD), and a duplex mode of the CC2 is time division duplex (TDD). The macro cell is controlled by a master eNodeB (MeNodeB), and the small cell is controlled by a secondary eNodeB (SeNodeB). The MeNodeB and the SeNodeB are connected by means of non-ideal backhaul, and consequently, a delay of exchange between the eNodeBs is relatively long.
When uplink transmission of UE is separately scheduled in two cells of dual connectivity, because of non-ideal backhaul, configuration information of one cell cannot be notified to the other cell in time; therefore, uplink scheduling of the UE in the two cells is relatively independent. For example, cells controlled by different eNodeBs cannot acquire a power headroom (PH) that is of another cell and that is reported by the UE. Consequently, total transmit power needed for the UE to perform sending in the cells may exceed allowed maximum transmit power, where the sending is scheduled in the two cells, and as a result, the UE reduces power, which increases a error probability of transmission; or transmit power that is of the UE and that is on each carrier may be very low, which causes a waste of power resources. In view of this problem, a scenario shown in FIG. 1 is used as an example. Both radio resource control protocol (RRC) functions of the two cells are controlled by means of RRC of the MeNodeB, the prior art proposes that PH-related physical layer information of the UE in the Small cell is sent to the Macro cell, so that the MeNodeB learns of a power use status of the UE in the Small cell according to PH-related physical layer channel configuration information of the Small cell and known RRC configuration information of the SeNodeB, and controls transmit power that is of the UE and that is in the Macro cell, to avoid that total transmit power that is of the UE and that is in the two cells exceeds maximum transmit power.
However, when the MeNodeB and the SeNodeB use independent RRC, in the prior art, the transmit power that is of the UE and that is in the Macro cell cannot be accurately controlled.